A variety of biopsy devices having sampling needles as part of their structure are available in the medical field. Typical biopsy devices include those that are designed to obtain samples from hard tissues, such as bone, and those that are designed for sampling of softer tissues. Soft tissue biopsy devices can include a structure whereby a sampling needle resides within an outer cannula and moves relative thereto during sampling. In particular, the operation of the device involves extending the distal end of the sampling needle beyond the distal end of the outer cannula to expose and introduce a portion of the needle to the tissue sampling site. A typical structure of a biopsy needle includes a sampling notch located proximal to the distal tip of the needle. The notch is configured to capture and house the sample once it is severed from the surrounding tissue. Subsequent to the capture of the tissue, the outer cannula is advanced in the distal direction over the notch of the needle to sever, trap and retain the sample during withdrawal of the device from the patient.
Soft tissue biopsy devices include manual, automatic and semi-automatic biopsy devices, which permit varying degrees of control over the biopsy procedure by the user. These devices can contain the mechanical elements to operate in a controlled rapid “firing” manner in which the tissue is penetrated by the sampling needle at a very high velocity. Such biopsy devices are described in Bauer U.S. Pat. No. 5,951,489, Bauer U.S. Pat. No. 5,916,175, Bauer U.S. Pat. No. 5,313,958, and Chu et al. U.S. Pat. No. 5,989,196.
Since the biopsy needle is a critical component in such rapidly-firing devices, the structure of the needle and its effect on sampling precision and the resulting trauma are important considerations. In addition to various notch designs, various tip configurations have also been explored. Beveled tips of biopsy needles having sampling notches are also known. One such beveled tip and sampling notch is described in Terwilliger U.S. Pat. No. 5,499,001. Another beveled tip configuration is present on the needle component of a Temno® II biopsy device available from Cardinal Health, Inc. (McGaw Park, Ill.).
There is a need in the medical device field for an improved biopsy needle for sampling soft tissues that possesses increased accuracy and maintains its structural integrity during its operation in biopsy procedures, such as when used in association with biopsy devices employing high velocity needle advancement. Particularly advantageous would be a biopsy needle for use in biopsy devices which, by virtue of its features, reduces or minimizes the amount of trauma to the patient during its use.